The present invention relates in general to solenoid valves, and in particular to a solenoid valve of the type having a solenoid provided with a plunger in the form of a permanent bar magnet which is coaxially displaceable in an exciter coil and polarized in the direction of its movement.
In the German published patent application No. 1,808,900 an electromagnetic drive suitable for driving a solenoid valve is described. This drive consists of an exciter coil and a longitudinally displaceable plunger which is in the form of a permanent magnet polarized in the direction of its movement. Another solenoid of this type is described in the German Offenlegungsschrift No. 1,489,088 in which the permanent magnet plunger consists of two permanent magnet segments which during the movement in the direction of displacement maintain a distance from each other. The north poles or south poles of these two magnetic segments are directed against each other. In a further operation of this known drive an intermediate piece of ferrite is provided between the two permanent magnetic segments. Even this modification is suitable for driving component parts of valves.